John Bongaarts at the Population Council thinks Climate Change has a good chance of limiting human Population but he is wrong

According to the new analysis by researchers at the United Nations and several academic institutions, there is an 80 percent chance that the world’s population, now 7.2 billion, won’t stop at nine billion in 2050, but will instead be between 9.6 billion and 12.3 billion by 2100. The researchers increased their estimates after noting persistent high birth rates and faster-than-expected progress in combatting HIV/AIDS in Africa. [Journal Science - World population stabilization unlikely this century]

Technology Review David Talbot says the prediction’s reliability is debatable, given that it does not take into account future hardships a large population would likely face. It doesn’t take into account the effects of climate change, food shortages, disease, or conflict. The study take into account that population growth could trigger deadly calamities like food shortages, war, and disease even without climate change, says John Bongaarts, vice president and distinguished scholar at the Population Council, a think tank and research organization based in New York City.

Wolfgang Lutz, director of the Vienna Institute of Demography, says, his newest analysis still suggests a less-dire outcome. “Our most likely scenario comes out somewhat lower than the current United Nations projections,” and suggests population will peak at 9.4 billion around 2070 and start a slow decline to nine billion by the end of the century.

So Lutz at the Vienna Demography Institute calls a human population rising to 12 billion in 2100 a dire outcome. It would be dire if wars, food shortages, disease and climate change do not limit population ? Or if Africa does not see vastly increased usage of birth control ?



Birth rates are suppressed during big wars but studies show that there is an increase in birth rates after the war and population levels recover.

Birth rates and populations also bounce back after famines.

Bongaarts seems to be hoping or expecting permanent wars and famines.

Africa has more wars and famines than other places in the world. This is one of the reasons that the birth rates stay high. People are worried that they will lose children. So they have 5-6 kids hoping that 2-3 will survive. When survival rates are good then birth rates are low. A lot of wars and famine and hardship means that people will have more kids and not less and population will be higher. There would have to be a complete global collapse for the population to drop and stay down. Bongaarts underestimates what people can do.

Large scale fish farming and ocean management (iron fertilization of the ocean to boost fish).
Bongaarts does not realize that all of the CO2 emissions and climate effects are side effects of our civilization. This is happening without that as a goal. Of course the technology exists and can be developed for changing the climate and the oceans to what we want. It is about getting the most economic and efficient solutions.

Ocean Acidification can be mitigated

Climate change can be mitigated.

Correcting soot pollution is 20 times cheaper than fixing the CO2

The World can support one hundred billion living at western levels and expected improvements in agriculture, energy and water can easily handle 15-20 billion by 2100.


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Africa potential and challenges for increasing agricultural yield

[NY Times] Africa’s agricultural yields are less than half the global average, and about 25 percent of what they could potentially yield. Agricultural productivity in Africa is growing at about half the rate the population is growing. Africa has long been a continent of small farmers, half of them women, raising maize with no fertilizer, pesticide or irrigation, on a tiny plot with a hoe. Now the little these farmers have is endangered by drought. Climate change is making Africa’s weather more extreme and erratic. Africa loses about a fifth of its maize crop because of drought. In many years, the loss is near-total. A survey of farmers in 12 countries found that in the last decade, they averaged about three wipeout years. In 2000, the first seeds for drought-tolerant maize were planted in Malawi and Zimbabwe. Now three million farmers in 13 countries in Africa are using them. (All these strains are conventionally bred, not genetically modified.) “One drought is something that throws farmers back into poverty,” said Bänziger. “They lose everything. During a severe drought, a farmer may harvest 5 percent of the ears of a normal crop. With drought-tolerant maize, the farmer can get 50 percent. We want to get to the point where we can save every plant.” Pesticides and inorganic fertilizers are bad for the environment. But this is not an argument that anyone who eats in America should be making to African subsistence farmers. In 2006, an African Union Declaration on agriculture adopted the goal of 50 kilograms of fertilizer per hectare planted. At the time, Africa was using only eight kilos per hectare; America was using 120. Africa needs vastly more fertilizer use, not less. The Green Revolution failed in Africa for reasons that remain major obstacles today. Absent research, roads, storage, extension capacity, credit and subsidies — high-yield maize will produce little, or its gains will go only to wealthier farmers.

Nation Master shows that the lowest agricultural yields are in Africa [mainly 2008 statistics]. Below are kilograms cereal grain yields per hectare. Developed countries have about 6000+ kg per hectare and the world average is about 3500 kilograms per hectare.